The Creosote Bush: The One and the Many
The creosote bush is truly the unnoticed elephant in the room. If someone were to weigh the biomass of the desert Southwest, this species would certainly possess the highest percentage of life and we would find that a high percentage of all other life in the desert is dependent upon it, yet its importance in the desert environment goes unappreciated by both scientists and artists alike. With the general public for instance, you'll find streets and cities named after the palo verde, the yucca, and the Joshua tree as well as many other plants and animals. However, I cannot think of any city or street or national park named after the creosote bush. No doubt this is because the creosote bush often looks like little more than a spindly olive colored pile of sticks that is dead and sterile. But if we take a closer look at the situation we will find that the creosote bush is neither dead or sterile but rather it is awesome; it has ability to live and thrive in the desert environment and provides for others. So if one wants to understand the environment of the desert Southwest, it is important to know the ways of the creosote bush.
And there's no better place to start with than the creosote bush’s inner reaction with the wind because it can be said that if you don't know the way the wind works in the desert environment you really don't know anything. With this in mind, when you look at a stand of creosote bushes you will see that they dramatically change the movement of the wind across the landscape as each bush slows down the wind and collects a pile of debris amongst its branches that consists of sand, dust, and leaves. This has a profound effect on the desert environment -it allows various grasses and annual plants to grow in this soil that is simply better than the soil beyond the influence creosote bush. This raised mound collected by the creosote bush makes it easier for lizards, insects, and other animals to dig into the ground. And this is due in part because of the attributes of the soil, the slight angle that the mound provides, and the biomechanics of the various animals. And because these various animals are digging in ground at the base of the creosote bush, it gives the soil a certain amount of churn that has benefits much like the plowing of a field. This allows for more grasses and other small annual plants to grow at the base of the creosote bush and thus we have one of many feedback loops that is part of the creosote bush environment.
And so we have the two basic design elements of the creosote bush which is of course the design and structure of the creosote bush and the mound that it collects. These two design elements are crucial to understanding how the creosote bush works in the rain. So we’ll start with an individual raindrop hitting one of the small creosote leaves. The leaves are covered with an oily creosote type substance and therefore shed the water fast and efficiently to the branches.
And these branches are smooth and hard, so they do not absorb much water and they generally have a very steep angle to the ground. All this means that the creosote bush will collect rain water from a relatively large area and deliver it to a relatively small area. And then some interesting things begin to happen as this water trickles from leaf to branch and then on to the ground where it often find its way into one of the many holes in the ground that the various animals have dug. Then this moisture goes deeper into the soil than it would have otherwise where it will be protected from the radiant energy of the sun and the dry winds that blow across the desert. And of course, this helps the creosote bush to survive and even thrive where other plants cannot and it also helps the grasses and small annual plants that grow amongst its branches which increases its effect on the wind and again, we have another feedback loop that is important to understand.
And then of course the shadow and reflectivity of the creosote bush has a major influence on the environment. To start with, the shadow of the creosote bush slows down the evaporation rate of the soil, thus allowing the small grasses and annual plants to sprout and grow to maturity whereas in the ground beyond, the creosote’s shadow dries out much faster. And so, when the creosote shadow holds the moisture long enough for these grasses and annual plants to grow, they too shadow the ground and thus filter out more of the sun’s radiant energy protecting the moisture in the ground creating yet another feedback loop.
This struggling little creosote Bush is very typical of the Mojave desert you can see that it has collected a small mound of dirt and there are a few holes in it.
And then we must also understand this plant’s ability to reflect the sun’s radiant energy onto the ground near it and the environmental effects of this phenomena. While this is often overlooked, to really understand the creosote environment, this reflectivity is important. So when you look at the south side of the creosote bush you’ll find that there is less plant life there and that’s because the creosote bush is reflecting some of the radiant energy of the sun onto the ground, thus elevating its temperature 5 or 10° and this is a very significant difference. Most of the time it means that the soil dries out faster and so there’s less plant life there.
However it doesn’t mean that the south side is any less important, it’s not just a dead zone. There is an important advantage to the south side of the creosote bush that can be seen easily when there is a light snow on the desert as the snow will melt on the south side of creosote bush much faster and thereby provide the warmth and moisture that some of the small grasses and annual plants need during the winter season. This provides a green and nutritional food source for a wide range of animals when there is nothing else there for them.
So far we have discussed how the individual creosote bush as a microclimate and therefore a microenvironment unto itself, however, to really understand the creosote bush we have to understand its collective power because it often exists in groups that number in the millions. And while a microenvironment may sustain a small lizard or a tarantula, it will not do for other animals, however, a large population of creosotes will make up a dot matrix environment that can sustain a large number of animals across the desert floor that otherwise could not survive there.
It goes something like this: a jack rabbit gets most or all of its moisture from the plants it eats and so it needs the microenvironment of the creosote to survive. However, one or two creosote bushes are not enough for it, but perhaps 1000 of these microenvironments will support a jackrabbit or two and so we find the jackrabbit is an integral part of the one and the many of the creosote bush environment and of course, the jackrabbit can also be understood with this same concept of the one and the many.
So while the microenvironment of the creosote bush is truly a wonder to behold, its dot matrix or collective power is what truly defines the environment of the desert Southwest and you will find this principle of the one and the many important in understanding the natural world whether it’s the creosote bush or the ponderosa pine; they both embody the principal of the one and the many.